Energy Transfer and Thermal Energy

Thermal Energy Transfer

​6 PS1.4

I can identify and exemplify the 3 ways thermal energy can be transferred.

Open Ended

Video Reflection: From the video you just watched, explain what you learned about thermal energy transfers.

Thermal Energy

The total kinetic (motion) energy of the tiny particles that make up matter; the faster the particles move, the warmer the matter becomes

As the particles in an object/substance move faster, the more thermal energy it has.

Kinetic Energy

This is the energy of motion

Particles are always moving; the faster the movement, the more thermal energy they have

So the higher the kinetic energy the higher the thermal energy.

The slower particles are moving, the less thermal energy they have

Open Ended

What is the relationship between kinetic and thermal energy?

Multiple Choice

An object whose particles are moving really slowly would be very...

• hot

• cold

• excited

• frozen

Heat Transfer

Heat will only move between objects of different temperatures.

Heat moves from a warmer object to a cooler object.

Heat will continue to move between objects/substances UNTIL both objects reach the same temperature.

Once both objects/substances reach the same temperature, this is known as EQUILIBRIUM.

Example- If you're holding an ice cube, heat will move from your hand to the ice cube until both reach the same temperature

Multiple Choice

Equilibrium is best stated as:

• two objects reaching the same temperature

• two objects with the same molecules

• two objects with the same mass

• two objects with the dame volume

Temperature

Average kinetic energy of all the particles in a material; measured by a thermometer in degrees (usually degrees Celsius or degrees Fahrenheit)

Higher the average kinetic energy= higher the temperature (feels hot)
Lower the average kinetic energy= lower the temperature (feels cold)

Open Ended

If the thermometer reading is high, what does this say about an object's/substance's amount of kinetic energy?

Open Ended

If you grab a metal handrail that is very cold, heat moves from ________ to _______

Conduction

Transfer of thermal energy that occurs in solids, liquids, and gases when two substances of different temperatures touch.

There must be contact between the two objects or substances.

In the image the heat from the fire is moving to the rod, and from the rod to the hand.

Conductors and Insulators

​Conductors are materials that will allow for conduction to occur (they allow thermal energy to pass through them easily.

Examples of conductors include steel, iron, copper, metal, and water

​Insulators are opposites of conductors. They will not allow for conduction to occur, thus thermal energy will not pass through them. They will stay cool to the touch.

Examples of insulators include wool, plastic, rubber, and wood.

Open Ended

Explain the process of convection.

Multiple Choice

Which of the following would be an example of conduction?

• sun warming the Earth

• ice melting in your hand

• you getting warmed by a campfire

• the wind blowing over a tree

Multiple Choice

In which state(s) of matter will conduction occur?

• solids

• liquids

• solids and liquids

• solids, liquids, and gases

Open Ended

Explain the difference between conductors and insulators.

Multiple Choice

All of the following are conductors EXCEPT:

• copper

• wood

• steel

• iron

Convection

This is a transfer of thermal energy through liquids and gases where warmer substances rise while cooler substances sink.

Molecules at warmer temperatures are less dense so they rise (spread apart).

Molecules at colder temperatures are more dense so they sink. (tightly packed together)

Convection is a cycle where warm liquids or gases rise, cool, get "heavy", and sink to be warmed again.

In the pot of boiling water, the warm water near the burner rises, displaces the cooler water at top, which causes the cooler water to sink to the bottom to be warmed and rise.

Open Ended

Explain the process of convection.

Fill in the Blank

Warm air/liquid is _____ _____ than cool air/liquid

Fill in the Blank

__________ __________ is an example of convection.

Multiple Choice

In which state(s) of matter does convection occur?

• gases

• liquids and gases

• solids and gases

• solids, liquids, and gases

Radiation

The transfer of energy by the movement of electromagnetic waves or subatomic particles.

Radiation occurs as thermal energy travels through empty space.

Radiation only occurs in gases.

The sun heating the earth, you warming by a campfire, and a person relaxing in a sauna are all examples of radiation.

Fill in the Blank

Radiation is the process of thermal energy traveling through __________ __________.

Multiple Choice

All are examples of radiation EXCEPT:

• boiling water for spaghetti

• sun heating the earth

• being warmed by a fire

• relaxing in a sauna

Open Ended

Choose either conduction, convection, or radiation, and give a real world example.

Multiple Choice

Which state of matter is steam?

• solid

• liquid

• gas

• plasma

Energy

The ability of a system to do work; required for changes to happen within a system.

Molecules are "working" as they move about constantly.

Multiple Choice

Which two forms of energy do particles have as they are "working"?

• electrical and solar

• kinetic and thermal

• light and chemical

• light and potential

Multiple Choice

If you are trying to keep your house warm in the winter, which do you want to use?

• conductor

• insulator

• solids

• gases

​On your notes paper, explain how conduction, convection, and radiation are all occurring in this image. Be prepared to share your thoughts.